MEASURED RESULTS
UN-BALANCED ATUs
TEN-TEC MODEL 238-B
At first glance, THIS ATU seems to be the winner. I will have to do a band-by band comparison to determine for sure.
IMPORTANT: The amount of RF Current in the transmission line is a factor of the antenna system impedance. High impedance means low current, and low impedance means high current.
This is very different from band to band.
DO NOT ATTEMPT TO COMPARE THE RF CURRENT VALUES BETWEEN BANDS.
MFJ-901
I found this ATU very difficult to adjust. I could not even find a match on the higher bands. Most likely this is due to the relatively small variable capacitors in the ATU (208 pF each).
Never the less, the bands that did find a match produced respectable results.
IMPORTANT: The amount of RF Current in the transmission line is a factor of the antenna system impedance. High impedance means low current, and low impedance means high current.
This is very different from band to band.
DO NOT ATTEMPT TO COMPARE THE RF CURRENT VALUES BETWEEN BANDS.
I will try to find another unbalanced ATU locally to borrow from a friend for further testing.
BALANCED (SYMMETRICAL) ATUs
ANNECKE SYMMETRIKAL KOPPLER
(original - "No Caps")
(Original Circuit)
According to the "MYTH", this ATU should be MUCH better than all the others.
It was not bad but the other balanced ATU's are as good or better.
"Without" the Caps Mod, it performed better on 80m.
IMPORTANT: The amount of RF Current in the transmission line is a factor of the antenna system impedance. High impedance means low current, and low impedance means high current.
This is very different from band to band.
DO NOT ATTEMPT TO COMPARE THE RF CURRENT VALUES BETWEEN BANDS.
MFJ-974-B
On 80m and 40m, this MFJ ATU came close to matching the TEN-TEC 238-B. On some higher bands it was better.
In Field Day (2008 and 2009) it clearly out-performed the Johnson Viking 275 W. Matchbox on an 80m dipole fed with 100 ft. of 450 Ohm Window-Line.
IMPORTANT: The amount of RF Current in the transmission line is a factor of the antenna system impedance. High impedance means low current, and low impedance means high current.
This is very different from band to band.
DO NOT ATTEMPT TO COMPARE THE RF CURRENT VALUES BETWEEN BANDS.
S-MATCH (DJ0IP Home-Brew)
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ANNECKE SYMMETRIKAL KOPPLER
(with "Caps Mod")
(Circuit with Caps Mod)
According to the "MYTH", this ATU should be MUCH better than all the others.
It was not bad but the other balanced ATU's are as good or better.
"With" the Caps Mod, it performed better on the higher bands.
IMPORTANT: The amount of RF Current in the transmission line is a factor of the antenna system impedance. High impedance means low current, and low impedance means high current.
This is very different from band to band.
DO NOT ATTEMPT TO COMPARE THE RF CURRENT VALUES BETWEEN BANDS.
DECCA KW EZEE MATCH
This ATU matched the ANNECKA on 80m and was best overall on 40m!
It will be interesting to see how it fairs in the band by band comparisons.
IMPORTANT: The amount of RF Current in the transmission line is a factor of the antenna system impedance. High impedance means low current, and low impedance means high current.
This is very different from band to band.
DO NOT ATTEMPT TO COMPARE THE RF CURRENT VALUES BETWEEN BANDS.
BLAH blah blah . . . (German Translation: "BLAH blah blah".)